Electronic piano-organ



June 25, 1940. J. MARKOWITZ ELECTRONIC PIANO-ORGAN Filed April 30, 1938 w TI.

IMTTORNEY.

Patented June 25, 1940 t H UNHTED STATES PATENT OFFICE ELECTRONIC PIANO-ORGAN Jerome Markowitz, Allentown, Pa.

Application April 30, 1938, Serial No. 205,226

1 Claim. (01. 25036) This invention relates to musical instruments such as oscillator units, which may include vacand has particular reference to electronic musical uum tubes. instruments employing oscillating tubes. Referring in detail to the drawing, at 45 is One object of the invention is the provision shown a vacuum tube oscillator device for proof an improved electronic tube operated organ ducing a piano effect in an instrument of the which shall be so small and compact as to be character described. The inductance I5 oomadapted to fit in anordinary console cabinet. prising honeycomb coils l6, has associated there- Another object of the invention is to provide with a condenser 20 of relatively large capacity. an organ of the type mentioned having improved The main output of the device may be taken at l0 means for obtaining bell and piano tonal effects 46 or 41, with the screen grid 48 actually serving from the same tubes that provide the sustained as the plate or main plate. In that sense the tones. plate 49 may be considered as an auxiliary plate, A further object of the invention is the proand the inventive feature resides in utilizing the vision of a device of the character described havsame to produce the tone of the piano effect, hejng few and simple parts, many of which may be cause the main output may uninterruptedly con- 15 of conventional or standard character, and which tinue to normally produce the Sustained oteis compact, inexpensive to manufacture, highly e p ly, he auxiliary plate 49 is constable, durable, reliable and eflicient in use. e e through a blOOkiIlg es sto 50 to a con- Other objects and advantages of the invention denser 5| which is adapted to be discharged by will become apparent as the specification proan instantaneous switch 52. The output circuit 20 ceeds, for the plate 49 is shown at 53. The parts 49 to With the aforesaid objects in view, the inven- 53 may be considered a unit 54 embodied in any tion consists in the novel combinations and ar- Suitable Orgall- Thus a e y 13011941 effec rangements of parts hereinafter described in their may be obtained, with the tone dy g out as the preferred embodiments, pointed out in the subcondenser 5| discharges. Y

joined claim, and illustrated in the annexed Heretofore condensers have been used to prodrawing, wherein like parts are designated by the V e decaying Voltage or tonal effects with same reference characters throughout the sev- Separate amplifier tubes. Also it W a e pted eral views. to produce such effects from the main plate of In t drawing; the oscillator, but this was unsatisfactory because 30 Figure 1 is a diagrammatic view of an mthe tube was turned on and 'off with resulting bodiment of the invention. shock thereto. 7

Fig. 2 is a similar view of a modification. At 55 is showna similar device for producing The advantages of the invention as here outa bell effect, this device differing from the device lined are best realized when all of its features 45 primarily in having a plurality of units such and instrumentalities are combined in one and as 54, as indicated at 56, in that they have disthe same structure, but useful devices may be charge condensers of different capacities, and produced embodying less than the whole. said units 56 having a common output. Thus It will be obvious to those skilled in the art to different overtones die out at diiferent rates to which the invention appertains, that the same produce the bell effect. More particularly, the 40 may be incorporated in several different conunits include auxiliary plates 51 connected structions. The accompanying drawing, therethrough blocking resistors to the respective confore, is submitted merely as showing the preferred densers 58, 59 of different capacities, each unit exemplification of the invention. having an output circuit 60 which are connected This application is a continuation in part of into a common output BI, and the condensers 58, 45 my applications as follows: Serial No. 151,349, 59 having instantaneous switches both actuated. filed July 1st, 1937, for Electrical musical instrusimultaneously as at 62 to discharge the conments; Serial No. 171,208, filed October 27th, 1937, densers 58, 59. In this device, a plurality of grids now Patent No. 2,140,267, issued December 13, 63, and a grounded blocking resistor at 64 are 1938, for Radio tube oscillators; and Serial No. provided, as the grid bias is low, the plate voltage 50 186,777, filed January25th, 1938, for Oscillators used should be low. It will be noted that this for electricalmusical instruments. arrangement really combines two tubes in one Generally described, the invention provides an envelope, and that the principle is applicable t electronically operated musical instrument such the use of two separate tubes. as an organ having a series of sound generators I claim: u

A device including an electrical musical instrument comprising an oscillator having a circuit including a space discharge tube having a cathode, a grid, and a second grid, the latter functioning as the anode, an inductance connected between the said grids, a condenser connected across said inductance, output means for said circuit, to which a constant voltage is applied,

whereby a sustained tone is produced, an auxiliary anode forming part of said tube to provide an electron coupled oscillator, a second output means connected to the auxiliary anode, and means for changing the voltage on said auxiliary anode to control the output signal voltage obtained from the auxiliary anode.

JEROME MARKOWITZ. 

